i. Field of Invention
The present invention relates to a device for the vertical and lateral displacement of a section of railway track. Stated more narrowly the present invention relates to a device for displacing rails laterally and vertically in which gripping members to grip the two lines of rails and mounted on at least one support frame connected by articulated connecting members to the chassis of a track maintenance vehicle which moves along the track. The support frame is both vertically and laterally displaceable relative to the vehicle by the action of lifting or lining means to displace the track section and bring it into a predetermined reference position.
II. Prior Art
Devices of the above type are already known but they cannot be used in all the construction variants encountered along railway tracks, particularly in zones where the track is crossed by apparatus such as switching or crossing points, movable switch rails, crossing cheeks or guide rails.
These devices are in fact the product of an assembly of known means first for lifting the track and secondly for lining the track. However the assembly has not been designed to resolve the problems posed by the combined lifting and lining of sections of track equipped with apparatus as described above. Hitherto for such sections use has been made of independent lifting or lining devices, each being suitable to a greater or lesser extent for the difficulties encountered as shown hereinafter.
Thus for lifting, a first solution comprises equipping the track maintenance vehicles with supplementary hooks used to grip the underside of the rail or even sometimes the sleepers themselves when it was not possible to use the gripping devices for the heads of the rails, e.g. when passing fish plates or switching points. A second solution consisted of increasing the number of gripping members spaced along the rails. These gripping members are generally rollers which roll on either side of the head of the rails in such a way that for example, on passing a fish plate at least one set of rollers can be in action beyond the fish plate whilst the other rollers are removed to pass the fish plate. However, such devices cannot be used to pass crossings and points or on the track close to crossings and points. In these places the free space necessary for their action on the sides of the rails to be gripped does not exist. In fact all the known lifting devices using gripping devices to grip either the rail head or the underneath of the tie plate of rails and they can only perform this gripping action by rotating the gripping member in a plane transverse and vertical to the track and inside and/or outside the track. This means that any obstacle in the immediate proximity to the rails to be gripped prevents their use. As this is the case when two rails join or come close together as well as adjacent points or a crossing there are always areas of the track which cannot be lifted mechanically by the known track equipment.
For lining purposes devices are known which use rollers supported on the upper face of the rail head. The rollers are provided with flanges applicable to either one or both sides of the rail head. However, quite independent of the fact that they do not permit the lifting of the track, it is vital to apply to them a vertical downwardly directed pressure onto the rail to .[.unable.]. .Iadd.enable .Iaddend.them to line the track laterally without the possibility of derailing the roller. This is clearly contrary to the effects sought in using the device namely the combined lifting and lining of a railway track. Devices are also known, such as pins or vertical journals, which can be applied to one flank of a rail head and devices combining the two above-mentioned devices. These devices can be effectively used for lining the track but cannot be used for lifting the track as they were not designed for this purpose.
The assemblage into a single device of the known devices does not solve the problems posed by the combined leveling and lining of sections of tracks equipped with apparatus as exemplified above. In fact as has been shown above either these devices cannot be used everywhere or the actions of constituent parts are incompatible.